Many conventional gauges require direct visual reading to determine the current level of fluid inside a tank, such as those used to store home heating oil. This task may or may not be convenient to conduct on a routine basis depending on the tank location. Furthermore, ongoing manual readings of a tank gauge are necessary to detect when the contents reach a critical level.
One method to overcome this problem involves the removal of an existing conventional gauge and installation of an electronic gauge that analyzes sound waves prior to wirelessly transmitting notification signals to a receiver located within close proximity. Should such an electronic gauge fail during use the owner/operator has no secondary method of reading the tank level until the defective gauge is replaced with a new one or a conventional gauge is reinstalled. Secondly, this design requires the owner/operator to properly install the electronic replacement gauge onto the tank so the liquid contents do not evaporate through an improper seal.
In addition to using sound waves to remotely monitor the level of a tank, a different method integrates reed switches that turn on and off when a magnetic field is present. Such a design requires the temporary removal of the measurement vial of an existing conventional gauge; installation of a magnet holder on top of the indicator; placement of a magnet on the holder; and re-attachment of the measurement vial. Once the magnet has been installed a sensor consisting of switches and other electronic components is strapped to the measurement vial for the purpose of turning designated circuits on and off. The state of each circuit is transmitted via wire cable to a second device for interpretation and level indication. Similar to the sound wave method, this design requires the owner/operator to properly install the required magnet on top of the gauge indicator and reattach the measurement vial onto the tank so the liquid contents do not evaporate through an improper seal. Furthermore, this system does not allow the owner/operator to monitor the status remotely from a location beyond the linear distance of cable installed between the transmitter and receiver.
What is needed is an optical sensor that can be fitted over a conventional tank gauge in order to provide remote access to the measurements generated by the conventional gauge.